Intersomatic cage, intervertebral prosthesis, anchoring device and implantation instruments

ABSTRACT

An intersomatic cage, an intervertebral prosthesis, an anchoring device and an instrument for implantation of the cage or the prosthesis and the anchoring device are provided. An intersomatic cage or an intervertebral prosthesis fit closely to the anchoring device, which includes a body of elongated shape on a longitudinal axis, of curved shape describing, along the longitudinal axis, an arc whose dimensions and radius of curvature are designed in such a manner that the anchoring device may be implanted in the vertebral plate of a vertebra by presenting its longitudinal axis substantially along the plane of the intervertebral space, where the anchoring device is inserted, by use of the instrument, through a slot located in at least one peripheral wall of the cage or on at least one plate of the intervertebral disc prosthesis to penetrate into at least one vertebral plate.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to French PatentApplication No. 07 04155, filed in FRANCE on Jun. 8, 2007.

TECHNICAL FIELD

This present invention concerns the area of orthopedic implants and moreprecisely of spinal implants, such as intervertebral prostheses andintersomatic cages.

BACKGROUND

An intervertebral prosthesis is implanted between two adjacent vertebraein order to maintain or restore a space between the vertebrae while alsopreserving good mobility. An intersomatic cage is implanted between twoadjacent vertebrae to allow the insertion and the growth of grafts ofbony tissue (or a substitute) in the disc space, in order to achieve anarthrodesis (fusion of two vertebrae). After insertion of the cage, theintervertebral space may be filled with self-adapting spongy bone orsuitable bony substitutes. The present invention concerns intervertebralprostheses and intersomatic cages for intervertebral fusion grafting andtheir attachment to the vertebrae by a bony anchoring device and theirimplantation in the disc space using implantation instruments.

A problem in this area concerns the stability of the intervertebralprostheses or of the intersomatic cages in the disc space after theyhave been implanted there, at least before the growth of the graft oneither side of the cage and fusion with the vertebrae in the case of theintersomatic cages. For example, there exists a risk that the prosthesisor the cage will move within the intervertebral space under the effectof the stresses exerted upon it when the patient moves. The prosthesisor the cage must therefore not only have a shape that prevents it frompivoting but also have resources to prevent it from moving within theintervertebral space.

From previous designs, we know of solutions that consist of equippingthe top and bottom surfaces of the prostheses or cages with notches soas to prevent movement. However, this type of solution is not perfectand the prosthesis or the cage still may move. We are also familiar,from previous designs, with solutions that consist of equipping theprosthesis or the cage with a bony anchoring device which is used tosoundly attach the prosthesis or the cage to the vertebral plates of thevertebrae between which it is implanted. This type of bony anchoringdevice proves to be effective for securing the prosthesis or the cage.However, this type of solution presents problems during implantation.

Access to the intervertebral spaces is often particularly difficultbecause of the dimensions involved, and in particular due to thepresence of blood vessels and nerves at the edges of the intervertebralspace. The bony anchoring devices must penetrate into the vertebrae to asufficient depth to secure the device. As a consequence, these bonyanchoring devices are generally implanted along an approach axis that ismore-or-less perpendicular to the plane of the intervertebral space orat least on a substantially oblique axis in relation to the plane of theintervertebral space. Other types of bony anchoring devices fit onto aplate that is substantially parallel to the axis of the vertebral columnand extending the prosthesis or the cage on one of the faces of thevertebrae. These different types of device therefore require thesurgeons to make large incisions, inducing prejudice and considerablerisks for the patient. In addition, this type of bony anchoring deviceis not easy to implant since it requires that there is sufficient spaceat the edges of the intervertebral space to allow the implantation ofthe device, which unfortunately is not always the case, depending on thevertebrae in question.

In this context, it is useful to provide an anchoring device (which maybe referenced below simply as a “device”) for an intersomatic cage or anintervertebral disc prosthesis that reduces the space at the edges ofthe intervertebral space that is necessary for the implantation of thecage itself, that makes the application of the anchoring device moreconvenient, or that provides better anchoring than some of the knownanchoring means.

SUMMARY

Some embodiments of this present invention have a purpose of overcomingcertain drawbacks of some previous designs by providing an anchoringdevice that is implanted solidly and at a sufficient depth in thevertebral plates to retain the cage against these vertebrae, but on anapproach axis that is substantially along the plane of theintervertebral space.

Some embodiments of this present invention have a purpose of overcomingcertain drawbacks of some previous designs by providing an intersomaticcage that is implantable substantially along the plane of theintervertebral space, which may be attached to the vertebrae by means ofan anchoring device that is implantable substantially along the plane ofthe intervertebral space.

Some embodiments of this present invention have a purpose of overcomingcertain drawbacks of some previous designs by providing anintervertebral prosthesis that is implantable substantially along theplane of the intervertebral space, which may be solidly attached to thevertebrae by means of an anchoring device that is implantablesubstantially along the plane of the intervertebral space.

Some embodiments of this present invention have a purpose of overcomingcertain drawbacks of some previous designs by providing an instrumentfor the implantation of an intersomatic cage or an intervertebral discprosthesis between the vertebrae and for the implantation of ananchoring device in at least one of these vertebrae, which may be usedto implant the cages or the prostheses substantially along the plane ofthe intervertebral space and to implant an anchoring device on anapproach axis that is substantially along the plane of theintervertebral space.

BRIEF DESCRIPTIONS OF THE DRAWINGS

Other particular features and advantages of various embodiments of thispresent invention will appear more clearly on reading the descriptionthat follows, provided with reference to the appended drawings, inwhich:

FIG. 1A represents a view in perspective of an anchoring deviceaccording to one method of implementation of the invention, FIG. 1Brepresents a view from above of an anchoring device according to anothermethod of implementation of the invention, and FIGS. 1C and 1D representviews in profile of anchoring devices according to two different methodsof implementation of the invention.

FIGS. 2A, 2B and 2D respectively represent a view in perspective, a viewfrom above and a view in profile of an intersomatic cage according toone method of implementation of the invention, FIG. 2C represents a viewin section of this intersomatic cage on section plane 2C-2C representedin FIG. 2B and FIG. 2E represents a view in section of this intersomaticcage on section plane 2E-2E represented in FIG. 2D.

FIGS. 3A and 3B respectively represent a view in perspective from thefront and a view from above of an intersomatic cage according to onemethod of implementation of the invention, FIG. 3C represents a view insection of this intersomatic cage on section plane 3C-3C represented inFIG. 3B and FIG. 3D represents a view in section of this intersomaticcage on section plane 3D-3D represented in FIG. 3B.

FIGS. 4A and 4B respectively represent a view in perspective from thefront and a view from above of an intersomatic cage according to onemethod of implementation of the invention, FIG. 4C represents a view insection of this intersomatic cage on section plane 4C-4C represented inFIG. 4B, and FIG. 4D represents a view in section of this intersomaticcage on section plane 4D-4D represented in FIG. 4B.

FIGS. 5A and 5B respectively represent a view in perspective and a viewfrom the front of a head for the implantation guide of an anchoringdevice according to one method of implementation of the invention, FIGS.5C and 5D respectively represent a view in perspective and a view inprofile of a guidance element for an anchoring device according to onemethod of implementation of the invention and FIG. 5E represents a viewfrom the front of the head of the guide equipped with two guidanceelements according to one method of implementation of the invention.

FIG. 6A represents a view in perspective of an implantation guide and ofan impactor according to one method of implementation of the invention,FIGS. 6B, 6C and 6D respectively represent a view from above, a view insection on section plane 6C-6C represented in FIG. 6B and a view insection on section plane 6D-6D represented in FIG. 6C of an implantationguide according to one method of implementation of the invention andFIG. 6E represents a view in profile of an impactor according to onemethod of implementation of the invention.

FIGS. 7A and 7C represent views from above of an assembly according toone method of implementation of the invention, of an implantation guide,of an impactor, of a cage and of an anchoring device, respectively,ready to be impacted and impacted, FIGS. 7B and 7D represent views insection of this assembly along section plane 7B-7B represented in FIG.7A and section plane 7D-7D represented in FIG. 7C, respectively.

FIGS. 8A and 8B represent views in perspective of an intersomatic cageequipped with an anchoring device according to one method ofimplementation of the invention and FIG. 8C represents a view inperspective of the end of an implantation guide carrying an intersomaticcage according to one method of implementation of the invention.

FIGS. 9A and 9B respectively represent a view in perspective and a viewfrom above, of the end of an implantation guide carrying an intersomaticcage equipped with an anchoring device according to one method ofimplementation of the invention and FIG. 9C represents a view in sectionon section plane 9C-9C represented in FIG. 9B.

FIGS. 10A, 10B and 10C respectively represent a view in perspective, aview from above and a view in section along axis 10C-10C of FIG. 10B, ofone method of implementation of a braced intersomatic cage and FIGS.10D, 10E and 10F respectively represent a view in perspective, a viewfrom below and a view in section along axis 10F-10F of FIG. 10E, ofanother method of implementation of a braced intersomatic cage.

FIGS. 11A and 11B respectively represent a view in perspective and aview in profile of one method of implementation of an intervertebralprosthesis equipped with anchoring devices, and FIGS. 11C and 11Drespectively represent a view in perspective and a view in profile ofanother method of implementation of an intervertebral prosthesisequipped with anchoring devices.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

This present invention concerns an anchoring device (1) that is usablefor intersomatic cages (2A, 2B) or intervertebral disc prostheses (2C).In various embodiments, the anchoring device (1) fits onto at least oneslot (20) located on the cage (2A, 2B) or the prosthesis (2C) that itsecures. This present invention also concerns intersomatic cages (2A,2B) and intervertebral disc prostheses (2C), which in variousembodiments may have a slot (20) or other receptacles adapted to receivethe anchoring device (1). This present invention also concerns aninstrument for the implantation of a cage (2A, 2B) or of a prosthesis(2C) and for implantation of an anchoring device to secure the cage (2A,2B) or the prosthesis (2C). In various embodiments, the instrument isdesigned for the anchoring device (1) so as to secure the latter in thevertebrae and also to the intersomatic cages (2A, 2B) or to theintervertebral disc prostheses (2C), which include at least one means(24) of retaining or attaching an implantation instrument so as to allowthem to be gripped or otherwise engaged by the instrument. Thisattachment device may include at least one recess (24) that accommodatesat least one gripping resource (321) of the instrument, as shown in theFigures and described below in greater detail. However, this attachmentresource (24) may also include a portion projecting on the outside ofthe cage or of the prosthesis and that is inserted into a recess of agripping resource (not shown). In addition, in certain implementationvariants, this attachment resource (24) may be formed at least in partby different surfaces of the cage (2A, 2B) or of the prosthesis (2C),with the gripping resources (321) of the instrument then having a shapethat is complementary to these surfaces so as to allow gripping of thecage or of the prosthesis.

Various embodiments allow a reduction in the dimensions of the deviceand of the associated instrument, so as to allow implantation of theanchoring device on an approach axis that is substantially along theplane of the intervertebral space (disc space).

The anchoring device (1) also may include a body (10) of elongated shapealong a longitudinal axis extending between a first end and a secondend. In this present description, the first end is called thepenetration end and the second end is called the abutment end. The body(10) of the anchoring device (1) of various embodiments may have acurved shape that, along the longitudinal axis, describes an arc, forexample a circular arc or an elliptic arc, whose dimensions and radius(or radii) of curvature are designed in such a manner that the anchoringdevice (1) is implantable in the vertebral plate of a vertebra bypresenting the longitudinal axis of the device (1) approximately alongthe plane of the intervertebral space. Various implementation variantsmay feature a differing radius (or radii) of curvature of the anchoringdevice (1). The device also may have several different radii ofcurvature on different portions of the body (10), or may have a radiusof curvature that varies along the body (10). Thus, this body may, forexample, have a shape of a circular arc or of an elliptic arc, but mayalso describe a more complex curvature, such as if several circulararcs, having the same radius of curvature or different radii ofcurvature, were end to end or if several elliptic arcs, having the sameradius of curvature or different radii of curvature, were end to end, oreven any combination thereof, or even a radius of curvature that is afunction of position along the body. In the present description, theterms “arc,” “circular arc,” and “radius of curvature” correspond to allthese possibilities.

Accordingly, some embodiments of this present invention providedifferent implementation variants regarding the radius of curvature ofthe anchoring device (1). For example, depending on the use of thedevice (1), and in particular of the vertebrae between which the cage orthe prosthesis is to be implanted, the device (1) preferably may have aradius of curvature that is greater or smaller in dimension in variousplaces. Depending on the radius of curvature of the anchoring device(1), the axes passing respectively through the penetration end andthrough the abutment end of the device (1) form an angle (AC), as may beseen particularly in FIGS. 1C and 1D. This angle (AC) typically will bein the range of 90° to 180°, inclusively, although it may also be chosento be less than 90°. Preferably, the angle (AC) will be between 110° and160°, which in many circumstances will facilitate the implantation ofthe device better than an angle (AC) outside this range. Depending onthe securing arrangement desired, an angle (AC) may be chosen that issubstantially open. For example, if it is desired to secure the cage orthe prosthesis by flattening it solidly against the vertebral plates, anangle (AC) will be chosen that ranges from 120° to 180°, while ifinstead it is desired to secure the cage or the prosthesis so as toprevent its movement in the plane of the disc space, an angle (AC) willbe chosen that is between 90° and 150°. Different implementationvariants may provide different angles for the anchoring device (1) tosecure the cage or the prosthesis. In one of the preferred methods ofimplementation, angle (AC) may have a mutually accommodating value, suchas close to 135°, for example, for securing the device by bothflattening the cage or the prosthesis against a vertebral plate andinhibiting the movement of the cage or the prosthesis in the plane ofthe disc space.

In addition, depending on the method of implementation of the cage or ofthe prosthesis, it is possible to choose different angles for thedevice, in particular to promote secure fixing despite a natural orpathological lordosis or one imposed by the prosthesis. The anchoringdevice (1) may be inserted through a slot (20) located on at least oneperipheral wall of the cage (2A, 2B) or on at least one plate of theintervertebral disc prosthesis (2C) and traverse at least one portion ofthis cage (2A, 2B) or of this prosthesis (2C). This slot (20) may extendfrom a peripheral surface of the wall (25) of the cage (2A, 2B) or ofthe plate of the prosthesis (2C) up to a top or bottom surface of thiscage (2A, 2B) or of this plate, with an orientation designed for theradius of curvature of the anchoring device (1), so as to orientate thelatter in the direction of the vertebral plate of one of the vertebraebetween which the cage (2A, 2B) or the prosthesis is implanted. By meansof this orientation of the slot (20), the anchoring device (1) maypenetrate into at least one vertebral plate and secure the cage (2A, 2B)or the prosthesis (2C) against this vertebral plate. Depending on theradius of curvature and the angle (AC) of the anchoring device (1), thethickness and the orientation of the slot (20) may vary in accordancewith the various methods of implementation.

Some embodiments of this present invention therefore provide anintersomatic cage (2A, 2B) that includes a peripheral wall (25) forminga cavity (23) that receives a graft of bony tissue or a substitute. Sucha cage may include a cavity (23) in its centre, formed by its wall (25),as shown in the Figures, but it may also, in other implementationvariants, consist of a block that does not have a cavity inside it, suchcage being, for example, used at least in pairs, so as to form a cavitybetween the cages as is known from the previous designs. In animplementation variant represented in FIG. 10A, the intersomatic cage(2A) includes a brace (27) traversing its cavity (23) from side to side,which may be configured to strengthen the wall (25) of the cage (2A).This brace (27) may have different forms and orientations and may, forexample, be orientated along the insertion axis of the cage (2A) betweenthe vertebrae. In various methods of implementation, the brace (27) mayhave a height that is less than that of the rest of the cage. Thissmaller height of the brace (27) in relation to the rest of the cage mayallow the cage to hug any shape irregularities of the vertebral plates.Thus, as illustrated, for example, in FIGS. 10A to 10C, the top andbottom surfaces of the brace (27) are located lower and higher than thetop and bottom surfaces, respectively, of the cage (2A). Thus, if thevertebral plates of the two adjacent vertebrae have bumps, the cage willfollow the shape of these plates and generally provide better stability.In this implementation example represented in FIGS. 10A to 10C, thebrace is not equipped with notches since it will not be in contact withthe vertebral plates. However, the brace (27) may nevertheless beequipped with notches (22), even in this case, for example, so as toenhance stability of the cage when the osseous graft has grown aroundthe cage. In the implementation example of FIGS. 10D to 10F, the bottomsurface of the brace (27) is located at the same level as the bottomsurface of the rest of the cage (2A) but the top surface of the brace(27) is located lower than the top surface of the rest of the cage (2A),as may be seen particularly in FIG. 10E. In this implementation example,the bottom surface of the brace (27) is equipped with notches (22)adding to the notches present on the rest of the cage in order to opposethe movement of the latter. In a variant, this brace may not includenotches. In a variant, this type of cage may also be used in an inverseconfiguration in relation to this example. Thus, in this variant, thebrace (27) will have a top surface at the same level as the top surfaceof the rest of the cage and a bottom surface located higher than therest of the cage. All of these possible variants of the brace maynaturally be combined with the other variants concerning the othercharacteristics of the cage.

In some embodiments of this present invention, the wall (25) of the cage(2A, 2B) includes at least one slot (20) having a width that allows thepassage of this anchoring device (1) despite its curvature. This slot(20) may have a width (the height of the aperture described by the slot)substantially larger than the height of the anchoring device (1), toincrease the ease of such passage. This slot (20) traverses the cage(2A, 2B) between a peripheral surface of the wall (25) and a top orbottom surface of the cage (2A, 2B), with an orientation that isdesigned for the radius of curvature of the anchoring device (1), so asto orientate the latter in the direction of the vertebral plate of oneof the vertebrae between which the cage (2A, 2B) is implanted.

Some embodiments of this present invention provide an intervertebraldisc prosthesis (2C). The prosthesis (2C) includes at least one firstplate (51) and one second plate (52) that articulate along a curvedsurface. In one method of implementation, particularly visible in FIGS.11A and 11B, the prosthesis (2C) includes only two plates (51, 52), eachof which has a curved surface. These curved surfaces of the two plates(51, 52) are complementary and fit together to allow an articulation ofplates (51, 52) by rotation about an axis that is more-or-lessperpendicular to the plane of the plates and/or by sloping the plates inrelation to each other. In another method of implementation that isparticularly visible in FIGS. 11C and 11D, the prosthesis (2C) includestwo plates (51, 52) and a central core (53), which is mobile in relationto at least one of the plates (51, 52). In one method of implementation,this core (53) includes a surface that is substantially plane, fittingonto a surface that is substantially plane of one of the plates (51, 52)and a curved surface fitting onto a complementary curved surface of theother plate (52, 51). The curved surface allows an articulation asdescribed previously (inclination and/or rotation) and the plane surfaceallows a linear movement of the core in relation to the plate thatincludes the plane surface and/or a rotation of the core in relation tothis plate, about an axis that is more-or-less perpendicular to theplane of the plates. In addition, according to the methods ofimplementation employed, the core (53) may include complementary matingresources (530) on at least one of the plates (51, 52) so as to limitthe movement of the core (53) in rotation and/or in linear movement inrelation to this plate. In some embodiments of the present invention, atleast one of the plates (51, 52) of the prosthesis (2C) includes atleast one slot (20) having a width that that allows the passage of thisanchoring device (1) despite its curvature. This slot (20) may have awidth (the height of the aperture described by the slot) substantiallylarger than the height of the anchoring device (1). Similar to someembodiments having an intersomatic cage (2A, 2B) discussed above, theintervertebral prosthesis (2C) may have one or more slots (20) thattraverse the plate (51, 52) and orient the anchoring device (1) in thedirection of the vertebral plate of one of the vertebrae between whichthe prosthesis (2C) is implanted. In some embodiments, the dimensionsand orientation of the slot(s) (20) may be adapted, respectively, to thedimensions and to the radius of curvature of the anchoring device (1).

In a preferred method of implementation of the invention, the width ofthe slot (20) will be slightly greater than the thickness of theanchoring device (1), sufficiently to allow the passage of the latterwithin the slot, but by sufficiently little to enhance retention of thecage (2A, 2B) or of the prosthesis (2C) by the anchoring device (1),without excessive play of the latter within the slot (20). In variousembodiments, the curvature of the device (1) along the abutment end maybe configured to interfere with the slot (20) sufficiently to enhancethe retention of the cage (2A, 2B) or of the prosthesis (2C) by theanchoring device (1). In certain methods of implementation of theinvention, the length of the slot (20) may be substantially to the sameas the width of the device (1) so that the latter has little or no playonce inserted into the slot (20). The length of the anchoring device (1)may be designed for the depth of the slot (20) to be traversed and tothe depth to which it must penetrate to the vertebral plates.

Thus, the anchoring device (1), by means of its radius of curvature andthe orientation of the slot (20) in which it is inserted, may beimplanted on an approach axis that is substantially along the plane ofthe intervertebral space, meaning the plane along which the cage (2A,2B) or the prosthesis (2C) is implanted, which facilitates the approachof all of the elements of the intervertebral prosthesis or cage and theanchoring device to the edges of the intervertebral space. In one methodof implementation, the arc described by the body (10) has dimensions,and a radius of curvature that are designed in such a manner that theanchoring device (1) is implantable in a vertebral plate on an approachaxis forming an angle with the vertical axis of the vertebral column ofbetween 40° and 140°, and preferably an angle of approximately 90°. Thisangle may vary for a given anchoring device (1) depending on thedimensions at the edges of the vertebrae, and may also vary from oneanchoring device (1) to another depending on the radius of curvature ofthe device (1) used and the angle (AC) formed between its abutment andpenetration ends.

In one method of implementation of the invention, the curved andelongated body (10) includes at least one curved plate, as may be seenparticularly in FIG. 1 (A to D). This plate may be substantiallyrectangular as shown in the Figures, but may naturally have variousshapes without moving outside the spirit of the invention. Likewise, inother implementation variants, the body (10) may include a curved rod,with the slot (20) then having a shape to suit the section of this rod,but the invention naturally allows other methods of implementation, inparticular regarding the shape of the body (10). In other implementationvariants (not shown), the body (10) of this anchoring device (1) mayinclude two plates (or two rods), generally parallel to each other, andconnected together at the abutment end by an inward-curving part thatfits onto a rod present at the centre of the slot (20) in the cage, forexample as described in U.S. patent application Ser. No. 10/483,563, orU.S. patent application Ser. No. 11/109,276, each of which isincorporated herein by reference.

The penetration end of the anchoring device (1) penetrates into thevertebral plate of one of the vertebrae between which the cage (or theprosthesis) is to be implanted. In one method of implementation of theinvention, the penetration end includes a chamfer (13) or a bevel tofacilitate the penetration of the device (1) into the vertebra, as maybe seen particularly in FIGS. 1C and 1D. In an implementation variant,this penetration end may also include an indentation (15), in the formof a V-shaped notch, for example, as shown in FIG. 1B, to facilitate thepenetration of the penetration end into the vertebral plates. Theabutment end is butted up against a surface of the cage or of theprosthesis that the device secures, so as to hold the latter against thevertebral plate, preferably firmly and tightly.

In different implementation variants of the anchoring device (1), theabutment end of the body (10) includes at least one stop element (11)that mates with at least one surface of the cage (2A, 2B) or of theprosthesis (2C) that the device (1) secures. In a complementary manner,in different implementation variants of the cage (2A, 2B) or of theprosthesis (2C), at the level of the peripheral surface of the wall(25), the slot (20) includes at least one stop element surface (21) thatmates with at least one stop element (11) of the anchoring device (1).In one method of implementation, particularly visible in FIGS. 1A and1D, the stop element (11) includes a projecting lug on at least one faceof the anchoring device (1). In the example shown, this stop elementconsists simply of a lug orientated toward the interior of the circle ofwhich the arc described by the body (10) forms part, but the lug mayadopt different orientations. The cage (2A, 2B) or the prosthesis (2C)may then simply include, below the slot (20), a contact surface for thisstop element (11). The stop element surface (21) of the cage (2A, 2B) orof the prosthesis (2C) may then include a peripheral surface of the wall(25) or of the plate (51, 52) to accommodate this projecting lug on atleast one face of the body (10) of the anchoring device (1). In anothermethod of implementation that is particularly visible in FIGS. 1B and1C, the stop element (11) includes two projecting lugs on the sides ofthe body (10). These two lugs may consist of two latches click-fitted inthe slot. In this method of implementation, the stop element surface(21) of the cage (2A, 2B) or of the prosthesis (2C) may include, forexample, two recesses (21) located on either side of the slot (20) toaccommodate two projecting lugs on the sides of the body (10) of theanchoring device (1). These two recesses may, for example, have a shapeand dimensions to suit the click-fitting of the lugs of the anchoringdevice (1). In addition, as may be seen particularly in FIGS. 11A and11C, the periphery of the plates form an opening at the level of theslot for the insertion of the device and the edge located between thisopening and the periphery of the plate forms a sort of rod onto whichthe stop element (11) of the anchoring device (1) may fit. Thus, thestop element (11) of the device (1) may consist of a curved portion thatclick-fits on the edge of the plate. Thus, the device (1) may beremovable (in many methods of implementation) and may be implanted inthe vertebrae and fitted onto the plates of the prosthesis after theimplantation of the latter between the vertebrae. This method ofimplementation allows adjustment, where appropriate, of the position ofthe prosthesis between the vertebrae before definitive securing.

In certain methods of implementation of the invention, the body (10)includes, on at least one of its sides, one or more flexible lugs (14)orientated toward the abutment end and forming a stop element to opposethe withdrawal of the anchoring device (1). As may be seen particularlyin FIGS. 1A and 1B, this flexible lug (14) may be present on the twolateral sides of the body (10), but it may naturally be located on asingle face of the body, such as the top or bottom face, for example.This (or these) flexible lug(s) (14) are used to secure the anchoringdevice (1) in relation to the cage (2A, 2B) or the prosthesis (2C), bymeans of their orientation in the direction of the abutment end. Whenthe device (1) is inserted into the slot (20), the lugs (14) fold upbecause of their flexibility, thus allowing the passage of the device(1) in the slot even if the width of the body (10) is substantially thesame as the length of the slot (20), as mentioned previously, as aresult, for example, of the recesses in the body (10) provided for thefolding over of these lugs (14) or by means of the shape of the body(10) in relation to the slot (20). The position of these flexible lugs(14) on the body (10) may also be arranged so that they emerge at theother side of the slot (20), along the bottom or top surface of the wall(25) of the cage (2A, 2B) or at the bottom or top surface of the plate(51, 52) of the prosthesis (2C). In this method of implementation, atthe bottom or top surface of the wall (25), the slot (20) may include atleast one stop element surface that mates with these lugs. On the otherhand, the position of these flexible lugs (14) on the body (10) may alsobe arranged so that they do not emerge from the slot (20), which maythen have at least one recess allowing the lugs (14) to unfold andoppose the withdrawal of the anchoring device (1).

In certain methods of implementation of the invention, the body (10) isequipped with notches (12) that are orientated so as to oppose thewithdrawal of the device (1) after it has been implanted in a vertebra.As may be seen particularly in FIGS. 1A and 1B, the number, thedimension and the shape of these notches (12) may vary according to theimplementation variants, without moving outside the spirit of theinvention.

Depending on the methods of implementation, the cage (2A, 2B) may havedifferent shapes. The description that follows gives some non-limitingimplementation variants with reference to the appended Figures, but thecage (2A, 2B) and the prosthesis (2C) may of course have other shapeswithout moving outside the spirit of the invention. For example, thecage (2A) represented in FIG. 2 (A to E) is substantially annular, witha periphery that is substantially circular, except at the location ofthe slot (20) for insertion of the anchoring device (1), at which pointit will be held by an implantation instrument (3, 4). The shape of thecage (2A, 2B) or of the prosthesis (2C) may vary, of course, and theshape of the end of the said instrument (3, 4) in contact with the cage(2A, 2B) or the prosthesis (2C) may vary as a consequence, according tosome of the methods of implementation. The cage (2A, 2B) and theprosthesis (2C) may, for example, have different shapes, whichpreferably have a slot (20) designed for the insertion of the device(1), and attachment resources (24) adapted to mate with one end of animplantation instrument. Depending on the methods of implementation,these attachment resources (24) may be associated with a particularshape of the cage (2A, 2B) or of the prosthesis (2C) close to theseattachment resources (24) to allow a good fit with the instrument or mayeven have such particular shapes fitting onto complementary shapes ofthe instrument. For example, the instrument may include a contactsurface fitting closely onto the shape of the prosthesis (2C) close tothe recess (24) and/or of the slot (20). Likewise, as mentionedpreviously, the cage (2A, 2B) may include a cavity (23) at its centre ornot, to the extent that it is common to implant several intersomaticcages (2A, 2B) in a given intervertebral space (on condition that thedimensions allow it). The cages thus implanted are generally used toenclose bony tissue (a graft) which will grow within the intervertebralspace and allow a fusion (arthrodesis) of the two vertebrae betweenwhich it is implanted. It is also common to use a substitute instead ofan osseous graft. In any event, the aim of the cage (2A, 2B) is torestore or maintain a space between the vertebrae. Before the growth ofthe graft and the fusion of the vertebrae, the cage (2A, 2B) shouldremain correctly in position in the disc space, and various embodimentsof this present invention facilitate its immobilisation.

Before the implantation of the anchoring device (1) used to maintain thecage (2A, 2B) in position, there may be a risk that the cage (2A, 2B)will move within the disc space. In certain methods of implementation,at least one of the top and bottom surfaces of the wall (25) willinclude notches (22) that prevent movement of the cage (2A, 2B) betweenthe vertebrae between which it is implanted. Likewise, at least one ofthe plates (51, 52) of the prosthesis (2C) may be fitted, on its surfacein contact with the vertebrae, with stabilisation resources, such asnotches or fins or any type of structure that may be used to prevent itsmovement between the vertebrae, so as to enhance stability of theprosthesis before it is secured by the anchoring device (1). Thus, atleast one of the top and bottom surfaces of at least one of the plates(51, 52) may include notches (22) that prevent movement of theprosthesis (2C) between the vertebrae between which it is implanted.According to various methods of implementation, these notches (22) orother stabilisation resources may have different orientations, so as toprevent movement of the cage (2A, 2B) or of the prosthesis (2C) in oneor more directions. For example, the notches (22) may be substantiallyparallel to each other and all orientated perpendicularly to the axis ofinsertion of the cage (2A, 2B) or of the prosthesis (2C), but on theother hand the notches (22) may have different orientations on differentportions of the cage (2A, 2B) or of the prosthesis (2C), so as toprevent movement in any direction.

In some situations, in particular depending on the vertebrae betweenwhich the cage (2A, 2B) or the prosthesis (2C) must be implanted, it isdesirable that the cage (2A, 2B) or the prosthesis (2C) allow theimposition of a lordosis or kyphosis in addition to maintaining thespace between the vertebrae. Certain methods of implementation thereforeprovide that the mean planes passing along the top and bottom surfacesof the cage (2A, 2B) form an angle (A1) that imposes a lordosis on thevertebrae between which the cage (2A, 2B) is implanted. For example,FIG. 2B represents a view from above of a cage (2A) according to onemethod of implementation of the invention. This cage is implantedsubstantially along axis 2C-2C representing, in FIG. 2B, the plane ofthe view in section of FIG. 2C. FIG. 2C shows that the mean planes (28)of the bottom and top surfaces of the cage (2A) form an angle (A1) whichimposes a lordosis along axis 2C-2C. On the other hand, in certainmethods of implementation, the mean planes passing along the top andbottom surfaces of the cage (2A, 2B) may be substantially parallel toeach other. Likewise, the prostheses (2C) may include plates whose topand bottom surfaces are substantially parallel to each other but mayinclude plates whose top and bottom surfaces form an angle that may, forexample, impose a lordosis or a kyphosis. Thus, in certain methods ofimplementation, the mean plane passing along the top and bottom surfaceof at least one of the plates (51, 52) of the prosthesis (2C) forms anangle (A1) that imposes a lordosis on the vertebrae between which theprosthesis (2C) is implanted, for example as described in U.S. patentapplication Ser. No. 11/109,276 or U.S. patent application Ser. No.11/098,266, each of which is incorporated herein by reference. In othermethods of implementation, the mean planes passing along the top andbottom surfaces of at least one of the plates (51, 52) of the prosthesis(2C) are substantially parallel to each other. In the case of prosthesesthat include a mobile central core (53) whose movement is limited bymating resources (530), the lordosis may be obtained by a core (53) thatat rest is moved off-centre by means of these mating resources (530)and/or the mating resources (531) of the plate.

In addition, in certain methods of implementation, the peripheral wall(25) of the cage (2A, 2B) may include at least one chamfer (250) on atleast one peripheral portion of at least one of its top and bottomsurfaces, so as to facilitate the insertion of the cage (2A, 2B) betweenthe vertebrae. As may be seen particularly in FIG. 2B, this chamfer(250) of the cage (2A) may be located substantially in the axis (2C-2C,FIG. 2B) of implantation of the prosthesis. In addition, as may be seenparticularly in FIG. 2D, this chamfer (250) may be present on the twobottom and top surfaces of the cage (2A). This chamfer (250) or bevelledprofile facilitates the implantation of the cage (2A, 2B) by accordingit a height that is somewhat less on its attacking edge (that isinserted first) than on the rest of the cage. Likewise, the plates ofthe prosthesis (2C) may include, on the periphery of their surface incontact with the vertebrae, at least one chamfer to facilitate theinsertion of the prosthesis (2C) in the disc space.

In certain methods of implementation, the peripheral wall (25) of thecage (2A, 2B) includes two superimposed slots (20) each of which isorientated toward one of the top and bottom surfaces, so as to allowanchoring of the anchoring device (1) in each of the vertebrae betweenwhich the cage (2A, 2B) is implanted. Likewise, each of the plates (51,52) may include a slot (20), each of which may be orientated toward oneof the top and bottom surfaces, so as to allow the securing of each ofthe plates (51, 52) by the anchoring of an anchoring device (1) in eachof the vertebrae between which the prosthesis (2C) is implanted. Inother methods of implementation, the cage (2A, 2B) may have only singleslot (20). In some embodiments, only one plate (51, 52) of theprosthesis (2C) has a slot and the other plate has none.

In certain methods of implementation, the cage (2A, 2B) may beimplantable on an axis located substantially along the plane of theintervertebral space but which is oblique in relation to the verticalaxis of the vertebral column so as, for example, to allow theimplantation between the vertebrae at the point at which blood vesselspass, preventing frontal access to the intervertebral space. In thiscase, the cage (2A) should be implanted on an axis of implantation thatis oblique in relation to the antero-posterior axis of the vertebralcolumn (the sagittal axis) meaning the axis in which a lordosis may haveto be imposed. As shown in FIG. 3B, the axis of insertion of theanchoring device (1) is orientated along axis 3C-3C, representing thesection plane of FIG. 3C and the cage (2A) is implanted on this axis,but because of the possible dimensions of the access to theintervertebral space, the antero-posterior axis of the vertebrae may beorientated along axis 3D-3D in relation to the cage, which may thus beimplanted obliquely. As may be seen particularly in FIG. 3A, and bycomparison with FIGS. 3C and 3D, cage (2A) may allow the imposition of alordosis by means of an angle (A1, FIG. 3A) of inclination between itstop and bottom surfaces, but the axis of inclination of the mean planes(28) passing along its top and bottom surfaces is orientated along axis3D-3D and not along axis 3C-3C. The cage therefore imposes a largerlordosis along axis 3D-3D than along axis 3C-3C in order that it may beimplanted along oblique axis 3C-3C in relation to axis 3D-3Dcorresponding to the antero-posterior axis of the vertebrae (thesagittal axis). Thus, a cage according to this particular method ofimplementation may be implanted obliquely and allow the imposition of alordosis that is aligned correctly with respect to the vertebral column.

In other methods of implementation, the peripheral wall (25) may includeat least two slots (20) located alongside each other, with each of thesedefining one possible axis of insertion of the anchoring device (1) inthe cage (2A, 2B) and, indirectly, one possible axis of insertion of thecage (2A, 2B) between the vertebrae. For example, as may be seenparticularly in FIGS. 4A and 4B, the cage (2A) includes 2 superimposedslots (20) each of which is orientated toward one of the top and bottomsurfaces of the cage on a first axis (4C-4C, FIG. 4B) located alongside2 superimposed slots (20) each of which is orientated toward one of thetop and bottom surfaces of the cage on a second axis (4D-4D, FIG. 4B).In this implementation variant, the cage (2A) may be implanted alongaxis 4C-4C or along axis 4D-4D but the inclination of the mean planespassing along the top and bottom surfaces of the cage is orientatedalong axis 4C-4C, as may be seen by comparison with FIGS. 4C and 4D.This type of cage may therefore be implanted obliquely (along axis4D-4D) or frontally (along axis 4C-4C). In a relatively similar manner,the plates (51, 52) of the prostheses represented in FIGS. 11A to 11Dinclude several slots (20) each. In the examples shown, these slots arelocated on the edges of the plates, but either centred in relation tothe antero-posterior axis of the prosthesis, or moved off-centre. Theseslots then define two possible axes of insertion of the osseousanchoring device (1), namely either on the antero-posterior axis, or onan oblique axis. In addition, the attachment resources (24) of theprosthesis (2C) are located close to each of these slots, so as to allowgripping of the prosthesis during the impacting of the device (1) in thevertebrae. Thus, these attachment resources (24) also define twopossible axes of insertion of the prosthesis (2C) between the vertebraeby the instrument, namely either an antero-posterior axis, or an obliqueaxis. After appreciating this disclosure, those of skill in the art willappreciate that the invention allows many variants regarding theposition and the shape of these attachment resources (24) and of theslots (20). It will be noted in passing that in FIGS. 11A and 11B, forexample, the devices (1) of the two anchoring plates do not have thesame orientation as each other, which may be explained by a differentorientation of their slot (20). Naturally, these Figures are simplyillustrative, and in no way limiting, since it is possible to envisageany type of combination of orientations and of shapes and of positionslots (20) on the plates after appreciating this disclosure.

In other methods of implementation, the intersomatic cage may be of thetransforaminal type, meaning implanted through the foramen. This type ofcage, which is described, for example, in patent application FR 06 01315and U.S. patent application Ser. No. 11,378,165 each submitted by thepresent applicant and which are incorporated herein by reference, isparticularly advantageous because it is relatively small and maytherefore be implanted by the transforaminal route. In various methodsof implementation of this present invention, the cage (2B) is in theshape of a circular arc, as may be seen particularly in FIGS. 8A and 8B,and includes at least one slot (20) of shape, dimension and orientationto suit the insertion of a curved anchoring device (1) according to thedifferent methods of implementation of this present invention. As may beseen particularly in FIG. 8A, the wall (25) of the cage may form acavity (23), internal or not, as for the cages (2A) describedpreviously. In addition, as may be seen particularly in FIG. 8A, thewall (25) may include at least one lateral opening (26) that allows thegrowth of the graft through the cage (2B). Although these lateralopenings have not been represented in the other Figures with referenceto the cages (2A) described previously, after appreciating thisdisclosure those of skill in the art will recognize that these too mayalso include such openings (26), where appropriate. This type of cage(2B) has an arcuate peripheral wall (25), for example describing acircular arc. The radius of curvature of the cage (2B) and thedimensions of the latter may naturally vary according to the methods ofimplementation, and according to the vertebrae between which they mustbe implanted. The wall (25) in an arc of the cage (2B) is extended, atone of its ends, by a return part extending in the direction of theinside of the curve described by the wall (25). In certain methods ofimplementation, as may be seen particularly in FIGS. 8B and 8C, thisreturn part may include a chamfer (250) to facilitate its implantationbetween the vertebrae. Like for the first implementation variants ofintersomatic cages (2A), these transforaminal implementation variants ofthe intersomatic cages (2B) may be equipped with notches (22) on atleast one part of at least one of their bottom or top surfaces. Whateverthe type of cage (2A, 2B), these notches (22) may have differentorientations and present a pattern that is linear or circular, or anyother type of pattern, and the lines or circles described by the notchesmay either cross each other or not. For example, as may be seenparticularly in FIGS. 8B and 8C, the notches (22) may describe a patternof chevrons or of circular arcs. The different methods of implementationof the anchoring device (1) described previously with reference to theprevious methods of implementation of intersomatic cages (2A) maynaturally be adapted to these transforaminal implementation variants ofthe cage (2B) and vice versa. Likewise, the different methods ofimplementation concerning the slots (20) may be adapted to this type oftransforaminal cage (2B) and vice versa, on condition that thedimensions allow it or are adapted to allow it.

In some methods of implementation, the intersomatic cages (2A, 2B) orthe intervertebral prostheses (2C) will be implanted by means of aspecial instrument (3, 4) that is used to implant them between thevertebrae and that may be used to implant the anchoring devices (1) inthe vertebral plates. In these methods of implementation, the peripheralwall (25) of the cages (2A, 2B) or at least one of the plates (51, 52)may include at least one attachment resource (24) that mates with agripper end of an instrument (3, 4) for implantation of the cage (2A,2B) or of the prosthesis (2C). As mentioned previously, this attachmentresource (24) may include at least one recess (24) that receives the endof a gripping resource (321). As may be seen particularly in FIG. 3A,the cage may include two recesses (24) each located on one side of theslot, to facilitate gripping of the cage, but the recesses of course maybe located in other places, preferably for these recesses to facilitatethe gripping of the cage (2A, 2B) or of the prosthesis (2C) by acomplementary instrument. As may be seen particularly in FIG. 4A, a slot(20) in the cage may be associated with a single recess (24) but it ispossible to provide several recesses (24) around the slots (20), evenwhen the cage (2A, 2B) includes several slots (20) as in thisimplementation example. These different variants concerning the numberand the position of the attachment resources (24) and of the slot (20)described here naturally apply equally well to the cages (2A, 2B) and tothe prostheses (2C).

Various embodiments of the present invention therefore also concern aninstrument (3, 4) for the implantation of an intersomatic cage (2A, 2B)or of an intervertebral disc prosthesis (2C) between the vertebrae andfor the implantation of an anchoring device (1) in at least one of thesevertebrae. The instrument may include an impactor (4) that includes ahead (40) whose shape and dimensions are designed to push on theanchoring device (1). The instrument may also include a guide (3) ofelongated shape on a longitudinal axis extending between a first end,called the gripping end of the cage or of the prosthesis, and a secondend, called the push end. The gripping end includes at least onegripping resource (321) that mates with at least one means (24) ofattaching the cage (2A, 2B) or the prosthesis (2C). Depending on themethods of implementation, the push end may include a handle (33) thatis used to push the guide holding the cage (2A, 2B) or the prosthesis(2C) in order to insert the latter into the intervertebral space. Thishandle may also consist of a stop element on which the surgeon may tap,by means of a tool of known type for example, in order to introduce thecage or the prosthesis between the vertebrae. After appreciating thisdisclosure those of skill in the art will recognize that the differentelements of the instrument (3, 4) described here may be present whateverthe method of implementation of the cage (2A, 2B) or of the prosthesis(2C), unless it is expressly specified in this present description thata particular element concerns only one type of cage described previouslyor a single type of prosthesis.

The guide (3) of the instrument may include a head (30) whose shape anddimensions are designed to at least partially accommodate the head (40)of the impactor, and includes at least one guidance surface (31) havinga radius of curvature that is substantially the same as the radius ofcurvature of the anchoring device (1). This curved surface (31) mayguide this anchoring device (1) through the slot (20) of an intersomaticcage (2A, 2B) or of an intervertebral prosthesis (2C), for the impactingof the anchoring device (1) into a vertebral plate of one of thevertebrae between which the cage (2A, 2B) or the prosthesis (2C) isimplanted.

The guide (3) may include an elongated body (32) that allows an approachto the intervertebral space without needing a lot of space. The impactor(4) also may include an elongated body (42), which slides in relation tothe body (32) of the guide (3). In certain methods of implementation,the impactor (4) includes a handle (41) which is used to cause the body(42) of the impactor to slide in relation to the guide (3). This handlemay also play the role of a stop element on which the surgeon may tap,by means of a tool of known type for example, in order to cause theanchoring device (1) to penetrate into a vertebral plate. In addition,in certain methods of implementation, the impactor (4) may include atleast one stop element (43) which limits the penetration of the head(40) of the impactor (4) within the head (30) of the guide (3). Incertain variants, the position of this stop element may be adjustablealong the body (42) of the impactor (4), for use in adjusting thepenetration of the impactor to the size of the head (30) of the guide(3) and to the size of the anchoring device (1) employed. For example,as mentioned previously, the anchoring device (1) may have a length thatis variable to suit the circumstances and the head (30) of the guide,and in particular the curved guidance surface (31) will also be of asize designed for this length of the anchoring device (1).

Depending on the methods of implementation, the body (32) of the guide(3) may have two rods or tubes (32), as shown in FIG. 6B, but the guide(3) may have a single rod or a single tube, even if the guide includesseveral gripping resources (321), preferably allowing these resources(321) to secure the cage or the prosthesis. As may be seen particularlyin FIG. 6D, in certain methods of implementation, the gripping resources(321) may consist of rods (321) fitted freely within the tubes (32)constituting the body of the guide (3). In some embodiments, these rodsmay not be within the body (32). In different methods of implementation,the gripping resource (321) may comprise one end of a rod which slidesin a body (32) of the guide (3) when it is operated by a handle (33) soas to enter and leave the recess (24) of the cage (2A). In theseimplementation variants, these gripping resources (321) may includethreads at their ends so as to be screwed within the recess (24) of thecage (2A, 2B), which may include a tapping. In certain implementationvariants, the rod (321) may therefore include a threaded end fittinginto a tapping in the recess (24) in order to secure the cage (2A) whenthe rod is operated by the handle (33). In other variants, the rod mayhave dimensions that are adjusted to penetrate exactly into the recess,and allow the retention of the cage by this exact adjustment. Thesedifferent variants of the rod (321) and of the recess (24) naturally mayalso be applied to prostheses (2C). For example, the prosthesesrepresented in FIGS. 11A to 11D include plates (51, 52) that includerecesses (24) to accommodate these gripping resources (321). In theexamples of implementation represented, the gripping resources (321) maybe located close to the top and bottom surfaces of the head (30) of theguide (3) so that these resources (321) allow the correct gripping oftwo plates (51, 52) of the prosthesis (2C). Various embodiments of theinvention allow other methods of implementation of the attachmentresources (24) and of the gripping resources (321), for example asmentioned previously. In addition, in the implementation example of theprosthesis (2C) of FIGS. 11C and 11D that includes two plates (51, 52)and a core (53), the attachment resources (24) may also includeattachment resources located on the core, so that the latter is alsoretained by the instrument. For example, the surface of the head (30) ofthe guide facing the prosthesis (2C) may have a shape that iscomplementary to the two plates and to the core assembly, so as to hugthe shape of the prosthesis and keep the elements of the prosthesisstable.

In the methods of implementation represented in FIG. 6 (A to E) and 7 (Ato D), the body (32) includes a guidance plate (34) that is used toguide the impactor (4). In these methods of implementation, the plate(34) includes a groove that guides the impactor on the axis of the body(32) of the guide. In other possible methods of implementation, asrepresented in FIG. 9A, for example, the body (42) of the impactor (4)may be mounted to slide within the body (32) of the guide, but theinvention naturally allows other implementation variants, preferablyallowing the impactor (4) to be guided in relation to the head (30) andto slide in relation to the guide (3).

As may be seen particularly in FIG. 5A, the head (30) of the guide (3)includes a cavity (300) whose shape and dimensions are designed toreceive the anchoring device (1) and, at least partially, the head (40)of the impactor (4). Various embodiments of the invention naturallyallow different methods of implementation of the head (30) and theexamples given here are only by way of illustration. The head (30) ofthe guide may include at least one passage (320) through which thegripping resource (321) of the cage or of the prosthesis will beinserted in order to hold the cage or the prosthesis at the end of theguide (3). In the method of implementation represented in FIGS. 5A and5B, this head includes two identical passages on either side of thecavity (300), since this method of implementation of the head (30) isdesigned to be mounted on a guide (3) that has two gripping resources(321). After appreciating this disclosure those of skill in the art willrecognize that the invention will allow the use of only one grippingresource (321) or, on the other hand, an increase in their number byreducing their size and by distributing them differently around thecavity, for example, with the provision of complementary recesses on thecages to be implanted. In addition, a given instrument (3, 4) may servefor the implantation of different types of cages (2A, 2B) or prostheses(2C), preferably with the gripping resources (321) of the guide (3) andthe attachment resources (24) of the cages (2A, 2B) or of the prostheses(2C) being designed to be complementary. For example, the instrumentthat includes a head (30) as represented in FIG. 5E, may serve for theimplantation of the cage (2A) of FIG. 4A, even though one of thegripping resources (321) of the guide (3) will not be used in this case.Inside the cavity (300) of the head (30) of the guide (3) there may beat least one curved guidance surface (31) of the anchoring device (1).In the methods of implementation illustrated here by way of example,this guidance surface (31) may include at least two curved grooves (31)each located on either side of this cavity (300) to guide the anchoringdevice (1) on both sides of its body (10). The head (40) of the impactor(4) is then designed to penetrate into the cavity (300) from one end tothe other of these grooves (31), so as to push the anchoring device (1)from one end to the other of these grooves (31). In the method ofimplementation represented in FIG. 5 (A to E), the cavity (300) of thehead (30) may receive two guidance elements (310) (particularly visiblein FIGS. 5C and 5D), with each including the guidance grooves (31) andeach located on one side of the cavity (300), as may be seenparticularly in FIG. 5E. In this implementation example, the guidanceelements (310) are assembled with the head (30) by inserting it into thecavity (300) which may include securing resources that are used toimmobilise these guidance elements (310). In other examples ofimplementation such as, for example, the head (30) of the guide (3)represented in FIGS. 8C and 9 (A to C), the head (30) will be made withof the guidance grooves (31) directly on the inside of the cavity (300).In this case, the head may be made in two assembled parts in order tofacilitate the machining of the curved grooves (31).

In certain methods of implementation, as shown in FIGS. 3A, 4A and 5A,the recess (24) of the cages (2A) may be created close to the slot (20),and the passage (320) for the gripping resources (321) may be close tothe cavity (300) so as to allow correct gripping of the cage close tothe site at which the anchoring device (1) is likely to apply pressureon the cage under the action of the impactor (4). The resource (24) forattachment of the prostheses (2C) may naturally be made in the same way.

As may be seen particularly in FIGS. 6C and 9B, the gripping resource(321) may protrude beyond the head (30) of the guide (3) at the positionof the gripping end. As may be seen particularly in FIGS. 7A and 7B orin FIGS. 9A and 9C, the guide may allow the gripping of the cage (2A,2B) with one end of the guidance surface (31) ending in the slot (20) inthe cage (2A, 2B) thus held, and the other end of the guidance surface(31) remaining accessible for the insertion of the anchoring device (1).In these methods of implementation, the anchoring device (1) may beinserted in the head (30) after the cage (2A, 2B) has been mounted onthe gripping resources (321), but other methods of implementation, whichmay be less advantageous but less costly to implement, may requireinsertion of the anchoring device (1) prior to the mounting of the cage(2A, 2B). These variants also may apply to the prostheses (2C) which maybe designed in the same way and may therefore be implanted with the sameinstrument as that described for these cages (2A, 2B).

In the case of the transforaminal cages (2B), the instrument may allowthe cage to be held over virtually the whole of its length, which mayfacilitate the insertion of the cage (2B) into the intervertebral spaceand protect it from damage. In this method of implementation of the cage(2B), the gripping resource (321) may be the end of a curved rod, suchas a spatula, which may have a radius of curvature substantiallyidentical to a radius of curvature of the cage (2B) having a peripheralwall (25) describing an arc. In this method of implementation, therecess (24) may be located on the return part extending one end of thecircular arc described by the wall (25) of the cage (2B) in thedirection of the centre of the circle of which the circular arcdescribed by the wall (25) forms part. The spatula may hug the shape ofthe cage (2B) between this return part and the other end of the circulararc described by the wall (25) of the cage (2B). At this other end ofthe wall (25), the cage (2B) advantageously may include a secondgripping resource to hold the cage (2B). In certain methods ofimplementation of the transforaminal cage, this second gripping resourcemay be located at the base of the spatula, but on the side opposite tothat carrying the spatula. This second gripping resource may include asecond recess (241) to accommodate a latch (341) mounted on a rod (340)of the guide (3). As explained previously for the body (32) of the guideand the body (42) of the impactor or the gripping resources (321), thisrod (340) may be mounted freely within the body (32) of the guide or onthe outside, preferably so that it is guided in relation to the head(30). This rod (340) may be operated by a handle and may pivot betweenat least one position at which the latch (341) engages the second recess(241), and a position at which the latch (341) exits from the secondrecess (241) and thus frees the cage (2B).

In certain methods of implementation of the implantation instrument (3,4), particularly suitable for the transforaminal cages whose insertionmust be accomplished along an arc or an oblique axis in relation to theantero-posterior axis of the vertebrae, the head (30) of the guide (3)may be curved or bent substantially along the radius of curvature of thearc described by the cage (2B). Thus, the bent instrument allows easierpassage through the foramens, although it may be used in anothercontext. In this bent method of implementation of the head (30) of theguide (3), the head (40) of the impactor (4) may have a shape that ismore or less curved or bent so that it has a radius of curvaturecompatible with its passage in the head (30) of the guide (3). Inaddition, in a particularly advantageous variant, this head (40) of theimpactor (4) may be mounted on an axis (425) of rotation mounted on thebody (42) of the impactor. This axis (425) allows the head (40) of theimpactor to pivot in order to pass the curvature or the bend in the head(30) of the guide (3), as may be seen particularly in FIG. 9B. Inanother implementation variant, the impactor (4) may be straight anddesigned to be inserted in the head (30) on an oblique axis,substantially parallel to axis 9C-9C of FIG. 9B for example, with thehead (30) then having an opening of sufficient size to allow theintroduction of the head (40) of the impactor (4).

After appreciating this disclosure those of skill in the art willrecognize that this present invention allows methods of implementationin many other specific forms without moving outside the scope of theinvention. As a consequence, these present methods of implementationmust be considered to be illustrations only, but may be modified withinthe area defined by the scope of the attached claims, and the inventionshould not be limited to the details given above.

1. An apparatus for implantation of a spinal implant comprising: anintersomatic cage configured for implantation in an intervertebral spacebetween adjacent vertebrae of a spinal column, the intersomatic cagecomprising a peripheral wall and a receptacle extending from a surfaceof the peripheral wall and traversing at least a portion of theperipheral wall, the receptacle configured for passage of an anchoringdevice having a body with a curved shape along a longitudinal axis thatdescribes an arc and for orientation of the anchoring device duringimplantation of the anchoring device in a vertebra; an anchoring devicefor anchoring the intersomatic cage between the adjacent vertebrae, theanchoring device comprising a body having an elongated shape along alongitudinal axis extending between a penetration end and an abutmentend, the body having a curved shape along the longitudinal axis thatdescribes an arc, and the body having dimensions and a radius ofcurvature configured for implantation of the anchoring device in one ofthe vertebrae by presentation of the longitudinal axis along an approachaxis that is substantially along a plane of the intervertebral space andby insertion of the anchoring device through the receptacle in theintersomatic cage with the anchoring device traversing at least aportion of the intersomatic cage; and an instrument comprising animpactor having an impactor head configured to push the anchoringdevice; and an elongated guide having a gripping end and a push end, theguide comprising a gripping device disposed at the gripping end andconfigured to grip the intersomatic cage, and a guide head configured toat least partially accommodate the impactor head, the guide headcomprising at least one guidance surface having a radius of curvaturesubstantially the same as the radius of curvature of the anchoringdevice and configured to guide the anchoring device through a receptacleof the intersomatic cage.
 2. An apparatus for implantation of a spinalimplant according to claim 1, in which the dimensions and radius ofcurvature of the body of the anchoring device are configured forimplantation of the device by presentation of the longitudinal axisalong an approach axis forming an angle of approximately 90° with thevertical axis of the spinal column.
 3. An apparatus for implantation ofa spinal implant according to claim 1 in which the body of the anchoringdevice includes at least one curved plate.
 4. An apparatus forimplantation of a spinal implant according to claim 1 in which thepenetration end of the anchoring device comprises a chamfer tofacilitate the penetration of the device into the vertebrae.
 5. Anapparatus for implantation of a spinal implant according to claim 1 inwhich the body of the anchoring device comprises notches orientated tooppose withdrawal of the device when implanted in a vertebra.
 6. Anapparatus for implantation of a spinal implant according to claim 1 inwhich the abutment end of the anchoring device comprises a stop elementconfigured to mate with a surface of the implant.
 7. An apparatus forimplantation of a spinal implant according to claim 6 in which the stopelement of the anchoring device comprises a projecting lug on a side ofthe body.
 8. An apparatus for implantation of a spinal implant accordingto claim 1 in which the body of the anchoring device comprises aflexible lug disposed along a side of the body, the flexible lugorientated toward the abutment end and forming a stop.
 9. An apparatusfor implantation of a spinal implant according to claim 1 in which thereceptacle of the intersomatic cage comprises a slot having a first stopconfigured to mate with a second stop of the anchoring device.
 10. Anapparatus for implantation of a spinal implant according to claim 9 inwhich the first stop of the intersomatic cage comprises a recessconfigured to accommodate a projecting lug of the anchoring device. 11.An apparatus for implantation of a spinal implant according to claim 9in which the first stop of the intersomatic cage comprises a portion ofthe surface of the peripheral wall configured to accommodate aprojecting lug of the anchoring device.
 12. An apparatus forimplantation of a spinal implant according to claim 1 in which thereceptacle of the intersomatic cage comprises a stop configured to matewith a flexible lug of the anchoring device to oppose withdrawal of theanchoring device from the receptacle.
 13. An apparatus for implantationof a spinal implant according to claim 1 in which the peripheral wall ofthe intersomatic cage comprises an attachment device configured to matewith a gripper of an implantation instrument.
 14. An apparatus forimplantation of a spinal implant according to claim 1 in which theintersomatic cage comprises top and bottom surfaces, at least one ofwhich having notches configured to prevent movement of the intersomaticcage when the intersomatic cage is implanted.
 15. An apparatus forimplantation of a spinal implant according to claim 1 in which theintersomatic cage comprises top and bottom surfaces each having a meanplane passing therethrough, and the mean planes are configured to forman angle configured imposes for imposing a lordosis on the adjacentvertebrae.
 16. An apparatus for implantation of a spinal implantaccording to claim 1 in which the intersomatic cage comprises pluralreceptacles, at least one of which plural receptacles is configured fororientation of the anchoring device during implantation of the anchoringdevice in a first one of the adjacent vertebrae and at least one ofwhich plural receptacles is configured for orientation of the anchoringdevice during implantation of the anchoring device in a second one ofthe adjacent vertebrae.
 17. An apparatus for implantation of a spinalimplant according to claim 1 in which the intersomatic cage comprisestop and bottom surfaces and in which the peripheral wall comprises atleast one chamfer on at least one of the top and bottom surfaces. 18.The apparatus according to claim 1 in which the guide head furthercomprises a cavity configured to receive the anchoring device and, atleast partially, the impactor head, and the guidance surface includes atleast two curved grooves disposed along adjacent sides of the cavity.19. The apparatus according to claim 1 in which the impactor comprises arod slideable in relation to the guide and operable by a handle.
 20. Theapparatus according to claim 19 in which the impactor comprises a stopelement configurable to limit travel of the impactor head with respectto the guide head.
 21. The apparatus according to claim 19 in which therod comprises a threaded end configured to engage a tapping in theintersomatic cage.
 22. The apparatus according to claim 1 in which theguidance surface is configured for a first end of the guidance surfaceto align with the receptacle of the intersomatic cage and for a secondend of the guidance surface to be accessible for the insertion of theanchoring device.
 23. The apparatus according to claim 1 furthercomprising a rod slideable in a body of the guide and operable by ahandle, and in which the gripping device comprises an end of the rodthat is configured to engage a recess in the intersomatic cage.
 24. Anapparatus for implantation of a spinal implant comprising: anintersomatic cage configured for implantation in an intervertebral spacebetween adjacent vertebrae of a spinal column, the intersomatic cagecomprising a peripheral wall and a receptacle extending from a surfaceof the peripheral wall and traversing at least a portion of theperipheral wall, the receptacle configured for passage of an anchoringdevice having a body with a curved shape along a longitudinal axis thatdescribes an arc and for orientation of the anchoring device duringimplantation of the anchoring device in a vertebra; an anchoring devicefor anchoring the intersomatic cage between the adjacent vertebrae, theanchoring device comprising a body having an elongated shape along alongitudinal axis extending between a penetration end and an abutmentend, the body having a curved shape along the longitudinal axis thatdescribes an arc, and the body having dimensions and a radius ofcurvature configured for implantation of the anchoring device in one ofthe vertebrae by presentation of the longitudinal axis along an approachaxis that is substantially along a plane of the intervertebral space andby insertion of the anchoring device through a receptacle in theintersomatic cage having dimensions and orientation adapted to thedimensions and radius of curvature of the anchoring device, with theanchoring device traversing at least a portion of the intersomatic cage;and an instrument comprising an impactor having an impactor headconfigured to push the anchoring device; and an elongated guide having agripping end and a push end, the guide comprising a gripping devicedisposed at the gripping end and configured to grip the intersomaticcage, and a guide head configured to at least partially accommodate theimpactor head, the guide head comprising at least one guidance surfacehaving a radius of curvature substantially the same as the radius ofcurvature of the anchoring device and configured to guide the anchoringdevice through a receptacle of the intersomatic cage.
 25. The apparatusaccording to claim 24 in which the guide head further comprises a cavityconfigured to receive the anchoring device and, at least partially, theimpactor head, and the guidance surface includes at least two curvedgrooves disposed along adjacent sides of the cavity.
 26. The apparatusaccording to claim 25 in which the impactor comprises a rod slideable inrelation to the guide and operable by a handle.
 27. The apparatusaccording to claim 26 in which the impactor comprises a stop elementconfigurable to limit travel of the impactor head with respect to theguide head.
 28. The apparatus according to claim 27 in which theguidance surface is configured for a first end of the guidance surfaceto align with the receptacle of the intersomatic cage and for a secondend of the guidance surface to be accessible for the insertion of theanchoring device.
 29. The apparatus according to claim 28 in which therod comprises a threaded end configured to engage a tapping in theintersomatic cage.
 30. The apparatus according to claim 24 furthercomprising a rod slideable in a body of the guide and operable by ahandle, and in which the gripping device comprises an end of the rodthat is configured to engage a recess in the intersomatic cage.
 31. Anapparatus for implantation of a spinal implant comprising: anintersomatic cage configured for implantation in an intervertebral spacebetween adjacent vertebrae of a spinal column, the intersomatic cagecomprising: a peripheral wall; and a receptacle extending from a surfaceof the peripheral wall and traversing at least a portion of theperipheral wall, the receptacle configured with dimensions andorientation that are adapted to receive an anchoring device having anarcuate shape along a longitudinal axis that is configured forimplantation in one of the vertebrae by presentation of the longitudinalaxis along an approach axis that is substantially along a plane of theintervertebral space and to orient the anchoring device duringimplantation of the anchoring device in a vertebra; an anchoring devicefor anchoring the intersomatic cage between the adjacent vertebrae, theanchoring device comprising a body having an elongated shape along alongitudinal axis extending between a penetration end and an abutmentend, the body having a curved shape along the longitudinal axis thatdescribes an arc, and the body having dimensions and a radius ofcurvature configured for implantation of the anchoring device in one ofthe vertebrae by presentation of the longitudinal axis along an approachaxis that is substantially along a plane of the intervertebral space andby insertion of the anchoring device through a receptacle in theintersomatic cage having dimensions and orientation adapted to thedimensions and radius of curvature of the anchoring device, with theanchoring device traversing at least a portion of the intersomatic cage;and an instrument comprising: an impactor having an impactor headconfigured to push the anchoring device; and an elongated guide having agripping end and a push end, the guide comprising a gripping devicedisposed at the gripping end and configured to grip the intersomaticcage, and a guide head configured to at least partially accommodate theimpactor head, the guide head comprising at least one guidance surfacehaving a radius of curvature substantially the same as the radius ofcurvature of the anchoring device and configured to guide the anchoringdevice through a receptacle of the intersomatic cage.
 32. The apparatusof claim 31 in which the body of the anchoring device includes at leastone curved plate.
 33. The apparatus of claim 32 in which the abutmentend of the anchoring device comprises a stop element configured to matewith a surface of the implant.
 34. The apparatus of claim 33 in whichthe stop element of the anchoring device comprises a projecting lug on aside of the body.
 35. The apparatus of claim 34 in which the body of theanchoring device comprises a flexible lug disposed along a side of thebody, the flexible lug orientated toward the abutment end and forming astop.
 36. The apparatus of claim 35 in which the receptacle of theintersomatic cage comprises a stop configured to mate with the flexiblelug of the anchoring device to oppose withdrawal of the anchoring devicefrom the receptacle.
 37. The apparatus of claim 34 in which thereceptacle of the intersomatic cage comprises a slot having a stopconfigured to mate with the projecting lug.
 38. The apparatus of claim37 in which the stop configured to mate with the projecting lugcomprises a recess configured to accommodate the projecting lug.
 39. Theapparatus of claim 38, in which the body of the anchoring devicecomprises a flexible lug disposed along a side of the body, the flexiblelug orientated toward the abutment end and forming a stop and thereceptacle of the intersomatic cage comprises a stop configured to matewith the flexible lug of the anchoring device to oppose withdrawal ofthe anchoring device from the receptacle.
 40. The apparatus of claim 33in which the intersomatic cage comprises plural receptacles, at leastone of which plural receptacles is configured for orientation of theanchoring device during implantation of the anchoring device in a firstone of the adjacent vertebrae and at least one of which pluralreceptacles is configured for orientation of the anchoring device duringimplantation of the anchoring device in a second one of the adjacentvertebrae.
 41. The apparatus according to claim 31 in which the guidehead further comprises a cavity configured to receive the anchoringdevice and, at least partially, the impactor head, and the guidancesurface includes at least two curved grooves disposed along adjacentsides of the cavity.
 42. The apparatus according to claim 41 in whichthe impactor comprises a rod slideable in relation to the guide andoperable by a handle.
 43. The apparatus according to claim 42 in whichthe impactor comprises a stop element configurable to limit travel ofthe impactor head with respect to the guide head.
 44. The apparatusaccording to claim 43 in which the guidance surface is configured for afirst end of the guidance surface to align with the receptacle of theintersomatic cage and for a second end of the guidance surface to beaccessible for the insertion of the anchoring device.
 45. The apparatusaccording to claim 44 in which the rod comprises a threaded endconfigured to engage a tapping in the intersomatic cage.
 46. Theapparatus according to claim 31 further comprising a rod slideable in abody of the guide and operable by a handle, and in which the grippingdevice comprises an end of the rod that is configured to engage a recessin the intersomatic cage.